It turns out that the barcode stripes encode data about the product name, which allows the cashier to quickly determine the purchase price with a special scanner, and also automatically calculate the total value of the receipt.

Roughly speaking, a barcode is a serial number in the store`s product list, thanks to which the computer program instantly knows the product name, its price, and performs sales accounting.

A barcode can do without numbers altogether, as all the necessary information is encrypted in the stripes, and the encoding algorithm is somewhat similar to Morse code. Numbers are only needed for information duplication. If for some reason the barcode is damaged and the scanner can`t read it, the cashier will enter the necessary numbers into the computer.

Although you can`t learn about the product`s composition from the barcode, its numbers contain a lot of useful information, for example, about the manufacturer.

The first 3 barcode digits indicate the country where the product was made. Moreover, large manufacturing countries can have several numbers at once.

The next four digits encode the manufacturer. This registration number is assigned by a special national organization. Since four digits can provide only 10,000 different combinations, for economy, one number can be assigned to several small companies in one industry.

The next five digits contain service information about the product type. Each manufacturer determines this number according to their own views. It can encode not only the product type but also its mass or packaging type, and also specify the factory if the previous 4 digits were the same for several manufacturers.

The last thirteenth code digit is the check digit and depends on the previous ones. To find out the meaning of this digit, first sum all the digits in the even positions of the barcode, then multiply the obtained number by 3, add the sum of the odd digits of the barcode to the result. Then subtract the last digit of the obtained number from ten. The result will be the check digit.

For clarity, let`s consider determining the check digit with an example. Suppose we have a barcode:

4607009520018, where 8 is the check digit.

Sum the digits in even positions and multiply the sum by three: 6+7+0+5+0+1=19;
19x3=57.

Sum the digits in odd positions:

4+0+0+9+2+0=15.

Now add the previously obtained numbers: 57+15=72.

Take the last digit from the obtained result, that is, two, and subtract it from ten:
10-2=8.

If the result is ten, then the check digit will be zero.

Some believe that the check digit serves to protect the buyer from counterfeits, but in reality, it`s intended for something else. It`s only needed so that the scanner`s automation can confirm the reading`s correctness and not ring up a marked bottle of wine at the price of mineral water due to a rubbed barcode.

Lately, designers are increasingly trying to create unusual barcode shapes, but that`s a separate topic. If the information about the meaning of the digits in the code proved useful to you, share it with your friends.